Transcript The System Unit

GIT 335
Computer Systems Technology
Lecture 4
Hardware
Dr. Thomas Schildgen, Professor
Arizona State University
Department of
Technology Management
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Lecture 4
Introduction to Information Technology
Content taken from the McGraw Hill Textbook Chapter 4
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Hardware: The CPU & Storage
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Microchips, Miniaturization, & Mobility
• Vacuum Tubes vs. Transistors
– Vacuum tubes were the original logic gates of computers
– They looked like light bulbs, were hot, and burned out
like them too
– The original transistors were 1/100th the size of vacuum
tubes (less power used, faster, more reliable too)
• Transistors vs. Integrated Circuits
– Compare 1955’s 45 lb “portable” color TV to today’s 7 oz
Casio 2.3 inch color TV
– One integrated circuit contains thousands of transistors
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Microchips, Miniaturization, & Mobility
• Semiconductor
– A material whose electrical properties are
intermediate between a good conductor and
a nonconductor of electricity
– Perfect substrate for overlay of complex
circuits
– Microchips are made from semiconductors
– Contain millions of microminiature integrated
circuits
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Microchips, Miniaturization, & Mobility
• Microprocessor
– The miniaturized circuitry of an entire computer
processor on a single chip
– Contains the CPU, which processes data
• Microcontroller or Embedded Computer
– A tiny specialized microprocessor installed in
“smart” appliances and automobiles
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The System Unit: The Basics
• Binary System: the basic unit of computing
– Uses just two numbers: 0 and 1
– All data and program instructions in the computer are
represented as binary
– Bit: each 0 or 1 is a bit
– Byte: a group of 8 bits
– Kilobyte: ~1,000 (1,024) bytes
– Megabyte: ~1 Million (1,048,576) bytes
– Gigabyte: ~1 Billion (1,073,741,824) bytes
– Terabyte: ~ 1 Trillion (1,009,511,627,576) bytes
– Petabyte: ~ 1 quadrillion bytes
– Exabyte: ~ 1 quintillion bytes
– All the printed material in the world is ~ 5 exabytes
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The System Unit: The Basics
• Binary coding schemes assign a unique binary code to each
letter
– EBCDIC
• Requires 8 bits per character
• Used for IBM mainframes
– ASCII
• Requires 7 or 8 bits per character, depending on the
version
• 8 bit Extended ASCII provides 256 characters
• Used for PCs, Unix hosts, Macs
– Unicode
• Requires 16 bits per character
• Handles 65,536 characters
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The System Unit: The Basics
• Error Checking: Parity Bits
– Used in modems & communications to verify
correctness
– One check bit is added to 7 bit byte
– The check bit is defined as either odd or even
– For odd parity, if the data sent is correct, the
parity bit plus the first 7 data bits is an odd
number
– For even parity, if the data sent is correct, the
parity bit plus the first 7 data bits is an even
number
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The System Unit: The Basics
• Machine Language
– A binary-type programming language built into
the CPU that is run directly by the computer
– Each CPU type has its own machine language
• Language Translators
– System programs convert the programming
instructions for you into machine language
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The System Unit: The Basics
The System Unit: The Basics
Computer Terms
•
Names
•
Definitions
1.
Bay
1.
2.
3.
Power Supply
Surge Protector
2.
3.
4.
4.
5.
Voltage
Regulator
UPS
6.
7.
8.
Motherboard
Microprocessor
Chipset
6.
7.
8.
Shell or opening used for the installation of electrical
equipment.
This converts AC to DC to run the computer.
Protects the computer from being damaged by power
spikes. Plug your computer into one.
Protects a computer against brownouts or low power
conditions that happen a lot in summer.
Uninterruptible Power Supply. Battery-operated device
that provides power for a time when there is a blackout.
The main system board of the computer.
The miniaturized circuitry of a computer processor.
Groups of interconnected chips on the motherboard that
control information flow between the microprocessor
and other system components connected to the
motherboard.
5.
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The System Unit: The Basics
• The CPU
– Older CPUs processing speeds are in
MegaHertz
• 1 MHz = 1 Million ticks per second
– Current CPUs processing speeds are in
GigaHertz
• 1 GHz = 1 Billion ticks per second
– The faster a CPU runs, the more power it
consumes, and the more heat it generates
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The System Unit: The Basics
• The CPU Continued
– Mainframe and minicomputer speed is measured in MIPS
• MIPS stands for millions of instructions per second
• Workstations perform at 100 MIPS or more
• Mainframes now perform as fast as 981,024 MIPS
– Supercomputer processing speed is measured in flops
• Flops stands for floating point operations per second
• Los Alamos Lab’s new Roadrunner cranks out 1
petaflop or 1,000 trillion operations per second.
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More on the System Unit
Parts of the CPU
Name
1. Word size
2. Control
unit
3. Arithmetic
Logic Unit
4. Registers
5. Buses
Definition
1. The number of bits the processor can
process at any one time
2. The part of the CPU that deciphers
instructions and carries them out
3. The ALU performs mathematical and logical
operations and controls the speed of them
4. High-speed storage areas that temporarily
store data during processing
5. Electrical data roadways used to transmit bits
within the CPU and between CPU and other
motherboard components
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More on the System Unit
How Memory Works
1.
Memory Chip
RAM
2.
ROM
1.
2.
3.
CMOS
3.
4.
Flash
4.
Explanation
Random Access Memory chips are volatile and
hold:
a. Software instructions
b. Data before & after the CPU processes it
Read only memory
a. Cannot be written on or erased without
special equipment
b. Are loaded at factory with fixed start-up
instructions
Complementary Metal Oxide Semiconductor
a. Powered by a battery
b. Contains time, date, calendar, boot password
Nonvolatile memory that can be erased and
reprogrammed more than once
a. Doesn’t require a battery
b. Used in newer PCs for BIOS instructions
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More on the System Unit
Types of RAM
RAM Types
1. DRAM
Explanation
1. Dynamic RAM must be constantly refreshed
by the CPU or it loses its contents
2. SDRAM
2. Synchronous Dynamic RAM is synchronized
by the system clock and is much faster than
DRAM
3. Static RAM is faster than DRAM and retains
its contents without having to be refreshed
by CPU
4. Double-data rate synchronous dynamic RAM
5. Single Inline Memory Module has RAM chips
on only one side
3. SRAM
4. DDR-SDRAM
5. SIMM
6. DIMM
a. FPM is fast page mode type
b. EDO is extended data output; is faster than
FPM
6. Dual Inline Memory Module has chips on both
sides
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More on the System Unit
Speeding up Processing
• The CPU works much faster than RAM
– So it could sit there waiting for information
– Cache temporarily stores instructions and data
that the processor uses frequently to speed up
processing
• Level 1 cache is part of the microprocessor
– Holds 8 to 256 kb
– Faster than Level 2 cache
• Level 2 cache is SRAM external cache
– Holds 64 kb to 2 Mb
• Level 3 cache is on the motherboard
– Comes on very high-end computers
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More on the System Unit
Speeding up Processing
Method
1. Interleaving
2. Bursting
3. Pipelining
4. Superscalar
Architecture
5. Hyperthreading
1.
2.
3.
4.
5.
Description
CPU alternates communications between
two or more memory banks
CPU grabs a block of data from memory
instead of retrieving one piece at a time
CPU doesn’t wait for one instruction to
complete before fetching its next
instruction
The computer can execute more than one
instruction per clock cycle
A technique used in superscalar
architecture in which the OS treats the
microprocessor as though it is two
microprocessors
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More on the System Unit
Ports
Port Type
1. Serial Port
2. Parallel Port
3. SCSI Port
4. USB Port
Description
1.
Used to transmit slow data over long distances
a. Sends data sequentially, one bit at a time
b. Used to connect keyboard, mouse, monitors,
dial-up modems
2. For transmitting fast data over short distances
a. Transmits 8 bytes simultaneously
b. Connects printers, external disks, backups
3. Small Computer System Interface
a. Connects up to 7 devices in a daisy chain
b. Transmits data 32 bits at a time
4. Universal Serial Bus can theoretically connect
up to 127 peripheral devices in a daisy chain
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More on the System Unit
USB
• Goals
– Be low-cost
– Be able to connect lots of devices
– Be hot swappable
• People hate rebooting because it takes time
• Hot swapping means a device can be
connected/disconnected without rebooting
– Permit plug and play
• Devices are automatically configured when
they are installed – no need to download new
drivers
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More on the System Unit
USB Continued
• Standards
– USB 1.1 – the original standard
– USB 2.0 – the current standard for new PCs
– USB On The Go (OTG) – currently under
development
• Connectors
–
–
–
–
A – in USB Type 1.1 and 2.0
B – in USB Type 1.1 and 2.0
Mini B – in USB Type 2.0
Mini A – in USB OTG used for smaller
peripherals like cellphones
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More on the System Unit
Specialized Expansion Ports
Port Type
1. FireWire
2. MIDI
Description
1. Intended for devices working with lots of data
a. Used for camcorders, DVD players, TVs
b. Handles up to 400 megabits per second
2. Musical Instrument Digital Interface
3. IrDA
4. Bluetooth
a. Connects musical instruments
b. Used in creating, recording, editing, performing
music
3. Infrared Data Association: Infrared ports used to
make a cableless connection
4. Uses short-range radio waves that transmit up to
30 ft
a.
5. Ethernet
Connects computers to printers, keyboards,
headsets, even refrigerators
b. Named after King Harald Bluetooth, son of Gorm,
who united the Norway and Denmark. Ruled 910940 A.D.
5. The standard for linking all devices in a Local
Area Network
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More on the System Unit
Expansion Cards
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More on the System Unit
Expansion Buses
Bus
1. PCI bus
2. AGP Bus
Description
1. Peripheral Component Interconnect
a. For high-speed connections
b. 32 or 64 bits wide
c. Typically used for sound cards,
modems, high-speed network cards
2. Accelerated Graphics Port
a. Twice the speed of PCI bus
b. For Video and 3-D graphics cards
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Secondary Storage
Storage Types
1. Floppy and Zip disks
Descriptions
1. Removable disks.
2. Hard disks
2.
3. Optical disks
4. Magnetic tape
3.
4.
5. Smart Cards
6. Flash memory
7. Online secondary
storage
5.
6.
7.
a. Floppies store 1.44 MB
b. Zip disks store 100, 250, or 750 MB
Made from thin rigid metal covered with
magnetizable substrate. Most disks have 2 or
more platters
Removable CDs and DVDs
Thin plastic tape coated with magnetizable
substance
Like a credit card, but contains a
microprocessor and memory chips
Nonvolatile memory – no moving parts
Lets you store data on an online vendor’s
server
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Secondary Storage
Floppies and Zip Disks
• Floppies
• Zip Disks
– Flat piece of mylar plastic
inside a 3.5” plastic case
– Store about 1.44 MB
– Have a write-protect notch
– Data is recorded in tracks:
concentric recording
bands
– Formatting breaks the
tracks into small wedgeshaped sectors
– Read/Write head transfers
data between the
computer and disk
– Floppies DO wear out!
– Disks with a high-quality
magnetic coating
– Store 100, 250, or 750 MB
– Require a Zip drive; won’t
work on floppy drives
– Used to store larger files
than floppies can hold
– Zip disks wear out too!
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Secondary Storage
Hard Disks
 Thin, rigid metal, glass, or ceramic platters covered with a
substance that allows data to be held in the form of magnetized
spots
 The more platters there are, the higher the drive capacity
 Store data in tracks, sectors, and clusters
 Formatting creates a file allocation table that maps files to
clusters or inodes
 Typical file systems are VFAT & NTFS for Windows, HFS
and ext2 for Unix
 Drive heads ride on .000001” cushion of air, and can crash!
 Important data should always be backed up!
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Secondary Storage
Hard Disks
 Hard Disk Types:
 External Hard Disks – a freestanding disk drive
 Removable Hard Disk – inserted into a cartridge drive on
the PC
 Hard Disk Controllers
 EIDE – Enhanced Integrated Drive Electronics
 Supports up to 4 disks at 137 GB per disk
 Marketed as SATA, Fast ATA, Ultra ATA, ATA-2, ATA/100
 SCSI – Faster than EIDE controllers
 Fibre Channel – used in large servers – faster and costlier
than SCSI
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Secondary Storage
Optical Disks
 CDs and DVDs are Optical disks
 Data is written and read using lasers, not a disk head
 CD-ROM is Compact Disk Read-Only Memory
 CD-R is used for recording only once
 CD-RW is an erasable optical disk that can both record
and erase data over and over again
 DVD is a CD-style disk with extremely high capacity
 Stores 9.4 or more GB
 DVD-R is used for recording only once
 DVD-RW, DVD-RAM, DVD+RW are reusable DVDs
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Secondary Storage
Magnetic Tape
 Thin plastic tape coated with a substance
that can be magnetized
 Store terabytes of data
 Used in the form of tape cartridges
 Still popular for large backups because of their
large data capacity
 But don’t get it near a magnet as that will erase
it!
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Secondary Storage
Smart Cards
 Resembles a credit card, but contains a
microprocessor and memory chips
 May function on three levels: credit, debit, and/or personal
information
 Holds more information than standard magnetic-strip
credit cards; 8 – 40 MB of data
 Contact smart cards
 Must be swiped through card readers
 Can wear out from use
 Contactless smart cards
 Read when held in front of a low-powered laser
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Secondary Storage
Flash Memory
 Nonvolatile memory with no moving parts
 But the electronics can wear out
 Available as
 Flash memory cards
 Insert these into a flash port of a camera, handheld
PC, smartphone
 Flash memory sticks
 A form of flash memory that plugs into a memory
stick port
 Flash memory drives
 A finger-sized module of flash memory
 Plugs into the USB port of most PCs and
Macintoshes
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Secondary Storage
Online Secondary Storage
 Allows you to use the internet to back up
your data
 Sign up with a vendor and receive access to
software that allows you to upload your data to
that company’s server
 Files should be encrypted to maintain security
 Use only for vital files that require immediate
availability
 Use tape, removable hard disk cartridges, zip
disks, optical storage or tape for normal backup
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Future Developments in Processing &
Storage
 Moore’s Law
 Gordon Moore predicted the number of transistors on a
silicon chip will double every 18 months
 It has held up since the 1960s!
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Future Developments in Processing &
Storage
New Technology
1. M-RAM
2. OUM
3. Nanotechnology
4. Optical
Computing
5. DNA Computing
6. Quantum
Computing
Description of Processing Technology
1. Magnetic RAM uses miniscule magnets
rather than electrical charges
2. Ovonic Multiplied Memory stores bits by
generating different levels of low and
high resistance on a glossy material
3. Tiny machines work at a molecular level
to make nanocircuits
4. Uses lasers and light, not electricity
5. Uses strands of synthetic DNA to store
data
6. Based on quantum mechanics and stores
information using particle states
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Future Developments in Processing &
Storage
New Technology
1. Higher-density
disks
Description of Storage
Technology
1. Higher Density Disks
a.
Blank CDs are replacing floppy disks
since they hold up to 700 MB and cost
< $1 each
b. DVD disks hold up to 9.4 GB of data
currently
c. Perpendicular recording technology
allows 25% - 100% more data to be
stored on the same disk
2. Molecular
electronics
2. Polymer memory creates chips
that store data on plastics
a. Nonvolatile memory
b. Data is stored based on polymer’s
electrical resistance
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